RU5024U1 - TACHOMETER FLOW METER - Google Patents

Abstract

A tachometric flow meter comprising a housing, a rotor fluidly mounted in the flow, connected to conical valves, each of which together with a conical seat forms a hydrostatic thrust bearing, and a device for measuring the rotor speed, characterized in that at least one of the conical valve seats is made with the possibility of axial movement and preloaded by a spring to the rotor valve.

Description

SAFETY EXPENDITURE 01 EP

The proposed utility model relates to flowmeters and counters, having 1 rotating element (rotor), the rotation frequency of which is proportional to the flow / consumption; and in order to create a moment on the rotor, the kinematic energy of the measured flow is used. When measuring the rotor speed, the device operates as a flow meter, and when measuring the total number of rtbor revolutions, as a counter of the amount of passed substance.

A turbine-tachometric flowmeter with hydrodynamics is known; Ash balancing of the rotor, developed by the PShKh (see L.L. Boshniak, L.N.Byzov, Tachometric flowmeters1; Ery, ed. in which the axial position of the rotor is determined by two conical valves connected to the base, always open at a constant value, regardless of the flow rate.

In the process, the balancing of the rotor occurs automatically due to the alignment of the axial forces arising on the valves from the pressure difference during the flow of fluid between the conical surface of the valve and the fixed wall of the casing having a corresponding profile. A disadvantage of the known device is the significant hydraulic resistance to flow, and, as a consequence of this, a narrow range of measured flow rates. The hydraulic resistance of the mentioned flow meter is 0.5 ... 6 kg / civr with a range of measured flow rates of 100 ... 2000 g / s.

Also known is a flowmeter with hydrodynamic balancing of the rotor, made in the Angligi (see P.P. Kremlevsky Flowmeters and Counters, ed. Mechanical Engineering, Leningrad Branch, 1989, p. 290, Fig. 159), in which the rotor is located perpend It is linearly inlet to the flow and is made in the form of an axis on which two axial turbines and two valves are fixed, made in the form of disks with conical surfaces. When a flow occurs, a pressure difference arises at the inlet and outlet of the flowmeter, which raises the rotor, and the flow, divided into two branches, rotates the turbines at a speed proportional to the volumetric flow. The disadvantage of this design is also a large hydraulic resistance and a narrow range of measured flow rates, since a cale of two flow sections of the rotor, formed by the conical surface of the valve and the fixed / seat body, is always open by one and the same value, regardless of the flow rate.

The task of creating a useful 1 .delPT is to develop a tachometric flow meter with a hydrodynamically balanced rotor, providing a wide range of measurable flow rates.

The problem is solved due to the fact that in a tacho .. metric flowmeter containing a housing, a hydrodynamically fluidly balanced rotor connected to conical valves, each of which together with a conical seat forms a hydrostatic thrust bearing, at least one of the conical valve seats with axial displacement of axial displacement and preloaded by a spring to the rotor valve.

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- 2 The tachometric flow meter contains a transducer I guiding the autopath 2, made in the form of a central body with ribs having screw surfaces, pressed by a nut 3 to the housing 4, a rotor 5, made in one piece with a buckle-bladed impeller and two sided with a conical valve, which has a fixed seat is a housing 4, and another movable saddle 6 is installed with a support 7 and a spring 8 in the rectifier 9. The straightener 9, made in the form of a cross with thin-walled ribs on the central body, is fixed in the housing 4 with a nut 10.

Tachometric flowmeter operates as follows.

The flow of the working substance, for example, liquid, is set at a given pressure; at: the entrance to the flowmeter along arrow A and passes through a guiding apparatus 2, playing the role of a swirler.

After the swirler, the flow acquires rotational motion, the kinematic energy of which is expended by the potential energy of pressure, and rotates the rotor 5 with a frequency proportional to the volumetric flow rate of the liquid through the rectilinear impeller.

Under the action of the fluid pressure head, the conical valve of the rotor 5 is in the open position, and the liquid after the impeller of the rotor enters the rectifier 9 through two metering sections of variable profile formed by the conical surfaces of the valve of the rotor 5, body 4 and the movable seat 6. At the entrance to the movable seat 6 the fluid enters through openings of constant cross section made in the truncated part of the conical valve of the rotor 5. The rectifier 9 dampens the rotational movement of the fluid flow at the outlet of the flow meter.

- 3 When moving the fluid flow along the flow meter channel on a rotating rotor 4, opposite forces occur. One force arising due to the high-speed pressure of the liquid tends to move the rotor 5 in the direction of flow, and the force from the differential pressure that occurs on the conical valve, which acts as a hydrostatic thrust bearing, is straggled to move the rotor 5 in the opposite direction. At a certain position of the rotor, these oppositely directed forces equalize and the rotor 5 is in a stream in a state of hydrodynamic equilibrium, regardless of the magnitude of the flow velocity.

So, for example, with an increase in the flow rate of the fluid, its velocity head increases, the pressure drop across the valve of the rotor 5 increases and the seat 6, overcoming the force of the spring 8 moves along the flow and increases the metering sections of the conical valve.

When the force on the rotor 5 of the high-speed head is aligned with the opposite direction of the chute: in the hydrostatic conical thrust bearing, the axial movement of the rotor 5 stops, and it takes a new equilibrium position. When reducing the consumption of acidity, the process occurs in the reverse order. In the absence of fluid flow, the conical valve of the rotor 5, through the movable seat b, is pressed by the spring 8 to the housing 4 and is in the closed position. The rotor speed is converted into an electrical signal by a converter I, for example, magneto-inductance.

Thus, the working fluid passing through the tachometric flowmeter rotates the rotor with a frequency proportional to the volumetric flow rate, the axial position of the rotor, and therefore.

- 4 and the bore sections of the double-sided conical valve, integral with poTopoivi, is also proportional to volumetric flow rate and is determined on the one hand by the spring tightening force 8 and geometrically by the dimensions of the hydrostatic thrust bearings formed by the conical surfaces of the rotor valve 5, the movable seat and the housing 4, and on the other hand, by the force of the high-speed pressure of the flow.

The differential pressure drop across the conical valve of the rotor 5 occurs at a minimum flow rate and is determined by the preliminary tightening of the spring 8. When the flow rate increases, the pressure drop across the valve increases in proportion to the spring stiffness B ..

Therefore, the selection of the springs 8 provides a wide range of measured flow rates for a given higher total pressure loss along the flow meter path.

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Authors V.A. Zhodzishsky j.fsr, G.V. Kokin

Claims (1)

A tachometric flowmeter comprising a housing, a rotor fluidly mounted in the flow, connected to conical valves, each of which together with a conical seat forms a hydrostatic thrust bearing, and a device for measuring the rotor speed, characterized in that at least one of the conical valve seats is made with the possibility of axial movement and preloaded by a spring to the rotor valve.